COVID-19 resources address physical environment concerns

The Center for Health Design (CHD) has pulled together a number of resources to help health care organizations minimize the impact of COVID-19 and other infections and transmittable diseases in health care facilities.

Its Infection Control Toolbox has more than 25 resources that address how to keep environmental surfaces safe, proper cleaning methods, building an infection prevention team and designing bio-containment spaces.

CHD has also curated research and articles from its Knowledge Repository. The repository is sponsored by a number of CHD partners, including the American Society for Health Care Engineering. It provides open access to more than 600 resources, including key point summaries, articles and research citations.

The resources selected for their relevance to COVID-19 address issues such as airflow patterns for isolation rooms, HVAC filters and more.

For instance, researchers for the study “Secondary exposure risks to patients in an airborne isolation room: Implications for anteroom design” wanted to tackle questions surrounding airborne infectious isolation rooms (AIIR), which are effective in preventing airborne pathogens from circulating a hospital. However, the use of negative pressurization can cause air to flow in from adjacent spaces, increasing the chances of an isolated patient contracting a secondary infection.

The researchers tested the role of an anteroom in this case, and found that, “Using positive pressurization in anterooms can break the directional pathways of flowing airborne bacteria considerably.” The authors of the study say designers should carefully consider how spaces adjacent to an AIIR affect airflow into the isolation room and vice versa.

Another study that looks into airflow and isolation rooms is “Airflow patterns through single hinged and sliding doors in hospital isolation rooms — Effect of ventilation, flow differential and passage.”

The objective of this study was, “To examine the effect of simulated human passage, realistic ventilation rates, and supply-exhaust flow rate differentials on airflow patterns generated by hinged and sliding doors.” The impetus for the study came from concerns posed by health care worker movement in and out of negative pressure isolation rooms as they treat patients. The researchers explain that although several studies have looked into the issue in regard to single-hinged doors, few have compared hinged doors with sliding doors. The researchers found that a single sliding door resulted in less airflow escaping the isolation room and performed notably better than a single-hinged door. So much so that they recommend that sliding doors be the primary application for isolation rooms.

Another study included on the resource page is “HVAC filtration for controlling infectious airborne disease transmission in indoor environments: Predicting risk reductions and operational costs.” The setting for the study was a hypothetical office space of 500 square meters with 25 occupants, one of whom was infected with influenza. The study investigates the use of particle filters in HVAC systems as a way to reduce pathogen transmission. Researchers concluded that HVAC filters were effective in reducing transmission and were more cost-effective than outdoor air ventilation. Some of their findings included:

• If a filter is not installed, 15% of the occupants run the risk of getting infected.
• Installing a low-efficiency filter with a minimum efficiency reporting value (MERV) of 7 reduces the risk to 12%.
• Installing a higher-efficiency filter (MERV 13) reduces the risk to 10%.
• Installing a high-efficiency filter (MERV 16) or a HEPA filter reduces the risk by 35-40% relative to the MERV 7 filter.

As clinicians care for patients, these resources can help equip facilities professionals to ensure a safe physical environment in which that care takes place. To dig into these studies and others compiled by CHD, visit the center’s “COVID-19 Resources for Healthcare Facilities” page.